The invention relates to a piezoelectric wafer including piezoelectric vibration pieces such as crystal vibration pieces, piezoelectric vibration pieces to be broken off and separated from the piezoelectric wafer into individual pieces, and a piezoelectric vibrator in which a piezoelectric vibration piece is supportably mounted in a package.
As for the production of piezoelectric vibration pieces, typically, multiple pieces are obtained at once from one piezoelectric wafer.
In order to obtain multiple piezoelectric vibration pieces from one piezoelectric wafer, piezoelectric wafers may be conventionally fabricated by wet-etching a resist pattern formed by photolithography. As a result, a piezoelectric wafer may be obtainable that has a large number of piezoelectric vibration pieces, frame portions supporting the piezoelectric vibration pieces, and coupling portions coupling the piezoelectric vibration pieces to the frame portions, wherein the piezoelectric vibration are broken off at the coupling portions and separated into individual pieces (refer to JP 2013-207509A).
Some of the known piezoelectric wafers may have slits formed in the coupling portions in its width direction, which may be helpful in breaking off the piezoelectric vibration pieces. An example of such piezoelectric wafers having the break-off assisting slits is described referring to FIG. 1. A piezoelectric wafer 1a has piezoelectric vibration pieces 2a with metal bumps 11a and 11b formed thereon, frame portions 3 supporting the piezoelectric vibration pieces 2a, and coupling portions 4 coupling the piezoelectric vibration pieces 2a to the frame portions 3. The coupling portions 4 each have slits 13g1 to 13g3. These slits are formed so as to penetrate through front and back surfaces of the coupling portion 4 in its width direction to make the piezoelectric vibration pieces more easily breakable. The coupling portion 4 further has slit-less bridges 13g4 and 13g5 formed in a part thereof in the width direction among the slits 13g1 to 13g3.